Industrial water systems, such as cooling systems, boiler systems, materials processing streams, waste water systems, and the like, play an important role in industry, as a whole. Industrial water systems typically include a number of functional chemical components that must be monitored to ensure the efficiency and proper functioning of the water system. Functional chemical components include material added to the water system to affect some physical or chemical property of the system, such as buffers, mineral scale inhibitors, corrosion inhibitors, surfactants, dispersants, flocculants, biocides, and the like, as well as chemicals that are present in the water system as naturally occurring species or as a natural consequence of the system's function (e.g., dissolved oxygen in a boiler system or waste water stream, chemical reactants, heavy metals in a waste stream, acids, bases, chlorine, hardness ions, anions, and the like). Because of the ubiquitous and dynamic nature of industrial water systems, it is often necessary or desirable to monitor the presence, or level, of various chemical components in an industrial water system.
In many cases, direct measurement of a chemical component's concentration in a water system may be difficult or impractical due to limitations in analytical detection and identification techniques. In such cases, or when convenience dictates, inert materials are added to water systems to indirectly monitor a chemical component of the water system. For example, inert compounds, such as dyes (e.g., UV absorbers, visible light absorbers, fluorescent dyes, and the like) or radioactive materials, have been added to a water system in direct proportion to a functional chemical that has also been added to the system. Measurements of the concentration of the inert compound at various points during the operation of the industrial water system have then been used as an indicator of the presence and concentration of the chemical component of interest. The use of readily analyzable inert materials has gained popularity in water treatment applications, such as treatment of cooling water or boiler water to prevent corrosion and scale, in which the treatment chemicals, themselves, are difficult to detect, much less quantitatively determine.
Many of the current methods for monitoring components of water systems suffer from drawbacks and disadvantages that limit their broad applicability to a variety of water systems. For example, some types of dyes cannot be used as inert materials in particular water systems due to problems in the detection or quantitative measurement of the dye caused by interfering species in the water system (e.g., materials present in the system that mask the presence of and/or interfere with the detection of the inert material in the water system). In the case of many dyes, the interfering species may be colored compounds or particulate materials that preclude the quantitative detection of the inert material. Furthermore, current methods require a specific source and detector for each analyte, making quantitative detection of multiple analytes expensive.
Accordingly, there is an ongoing need and desire for selective and sensitive methods of monitoring chemical components in industrial water systems that are broadly applicable to a variety of water systems and analyses. The apparatus and methods of the present invention advantageously utilize room temperature phosphorescence to fulfill this need.